Light emitters are the key element in Organic Light Emitting Diodes (OLEDs) and photovoltaic cells. By far most of these devices are fabricated and perform under an inert atmosphere to keep their essential components from decomposing. However, these are expensive fabrication conditions, and are difficult to work in. There exists a need for light emitters that are stable at less stringent requirements. Additionally, Current light emitting devices have a limited range for the color blue, therefore there is significant need for new examples that broaden the range and increase the lifetime of devices.
The development of new molecular architectures to impart desired physical and chemical properties is an area of much activity. Numerous groups have developed examples of N-heterocyclic carbene ligands (NHCs) and their derivatives,1 originally reported by Arduengo,2 which are widely applied in catalysis3 and other areas.4 Pincer ligands are one of the most widely researched and applied architectures in modern organometallic chemistry.5 The confluence of NHCs and pincer ligand chemistry has seen much activity in recent years.6 The aryl-bridged bis(NHC)-pincer ligands are of two major classes depending on the atoms making the bonds to the metal: CCC-NHC pincer complexes (xylylenyl-bridged,7 phenylenyl-bridged systems8) and CNC-NHC pincer complexes (pyridylenyl-bridged,9 2,6-lutidenyl-bridged10). We have developed and disclose herein a unique class of CCC-bis(NHC) pincer ligand systems8 that emit light and remain stable in air and water.